PIPETTING DEVICE

Abstract

The invention relates to a pipetting device for receiving and dispensing fluid volumes. The pipetting device has a drive device with an electric motor and a gear device with a first output device. The gear device is driven by the electric motor by means of a rotary motion and is designed to transmit a rotary motion of the electric motor to the first output device. According to the invention, the gear device has a second output device and is designed to transmit a rotary motion of the electric motor to the second output device.

Claims

1-18. (canceled)

19. Pipetting device for receiving and dispensing fluid volumes, comprising a drive device with an electric motor, and a gear device, wherein the gear device is coupled to the electric motor in a manner enabling the gear device to be driven in a rotary motion, wherein the gear device has a first output device and a second output device, and wherein the gear device is configured to transmit rotary motion of the electric motor to the first output device or to the second output device.

20. Pipetting device according to claim 19, wherein the first output device is couplable or coupled to a displacement device, wherein the displacement device comprises a piston and a cylinder, the piston being movably arranged in the cylinder, and wherein the first output device is coupled to move the piston.

21. Pipetting device according to claim 19, wherein the first output device is couplable to the electric motor such that rotary motion of the electric motor is transformed into translatory motion of the first output device, and wherein the second output device is couplable to the electric motor such that rotary motion of the electric motor is transformed into translatory motion of the second output device.

22. Pipetting device according to claim 19, wherein the gear device comprises a threaded nut which can be motionally coupled with the electric motor, so that rotary motion of the electric motor causes a rotary motion of the threaded nut, and the first output device comprises a threaded spindle which is engaged with the threaded nut and is secured against rotation, so that rotary motion of the threaded nut caused by the electric motor causes translatory motion of the threaded spindle.

23. Pipetting device according to claim 19, wherein the gear device has a rotationally movable threaded part and the threaded part of the gear device can be motionally coupled to the electric motor, so that rotary motion of the electric motor causes rotary motion of the threaded part of the gear device, and the second output device has a translationally movable threaded part which is engaged with the threaded part of the gear device, so that rotary motion of the threaded part of the gear device caused by the electric motor causes translatory motion of the threaded part of the second output device.

24. Pipetting device according to claim 23, wherein the second output device is arranged coaxially relative to the first output device, and/or an axis of movement of second output device coincides with an axis of movement of the first output device, and/or the second output device at least partially surrounds the first output device, and/or the first output device is arranged at least partially in a hollow space of the second output device.

25. Pipetting device according to claim 19, wherein the pipetting device has a switching device by means of which the gear device can be switched in such a way that the gear device moves either the first output device or the second output device when the gear device is driven by the electric motor, and/or by means of which either the first output device or the second output device can be blocked against movement, and/or by means of which the gear device can be motionally coupled to the electric motor and motionally decoupled from the electric motor.

26. Pipetting device according to claim 25, wherein the switching device has means for: activating a movement of the first output device and for simultaneously deactivating a movement of the second output device, and/or activating a movement of the second output device and for simultaneously deactivating a movement of the first output device.

27. Pipetting device according to claim 25, wherein the switching device has a blocking device which is able to block at least one component of the gear device and/or block the first output device and/or block the second output device, wherein the blocking device has a locking mechanism, and/or is axially adjustable relative to an axis of rotation of the gear device, and/or is driven or movable by means of an activator of the pipetting device.

28. Pipetting device according to claim 27, wherein the pipetting device has an operating element for controlling the electric motor, by means of which the blocking device is controllable.

29. Pipetting device according to claim 19, wherein the gear device comprises an epicyclic gearing having a first central wheel, a second central wheel driven by the electric motor, which is arranged concentrically to the first central wheel and thereby rotates about a central axis, and at least one orbital wheel, each orbital wheel being rotatable about an orbital axis and being arranged between the first central wheel and second central wheel and respectively engaging the first central wheel and second central wheel, wherein the first central wheel and/or a carrier of the orbital wheel rotates about the central axis.

30. Pipetting device according to claim 29, wherein the epicyclic gearing is a planetary gearing, wherein the first central wheel has a hollow space, the second central wheel is arranged in the hollow space of the first central wheel, is driven by the electric motor and rotates about a central axis, each orbital wheel is arranged between the first central wheel and second central wheel in the hollow space and is engaged with the first central wheel and the second central wheel, respectively, and the first central wheel and/or a carrier of the orbital wheel rotates about the central axis.

31. Pipetting device according to claim 29, wherein the first central wheel can be blocked in such a way that no rotation of the first central wheel about the central axis is possible and a rotation of the second central wheel about the central axis causes a rotation of the carrier of the orbital wheel about the central axis, and the carrier of the orbital wheel can be blocked in such a way that no rotation of the orbital wheel or of the carrier of the orbital wheel about the central axis is possible and a rotation of the second central wheel about the central axis causes a rotation of the first central wheel about the central axis.

32. Pipetting device according to claim 29, wherein the orbital wheel or the carrier of the orbital wheel is motionally coupled to the first output device, wherein the gear device has a threaded nut and the threaded nut can be motionally coupled to the electric motor, so that in the coupled state a rotary motion of the electric motor causes a rotary motion of the threaded nut, the first output device comprises a threaded spindle which is engaged with the threaded nut and is secured against rotation, and the orbital wheel or the carrier of the orbital wheel is motionally coupled with the threaded nut, so that rotary motion of the orbital wheel or the carrier of the orbital wheel about the central axis causes rotary motion of the threaded nut and translatory motion of the threaded spindle.

33. Pipetting device according to claim 29, wherein the first central wheel is motionally coupled to the second output device, wherein the gear device comprises a rotationally movable threaded part and the threaded part of the gear device can be motionally coupled to the electric motor, so that rotary motion of the electric motor causes rotary motion of the threaded part of the gear device, the second output device has a translationally movable threaded part which is engaged with a rotationally movable threaded part of the gear device, and the first central wheel is motionally coupled to the threaded part of the gear device, so that rotary motion of the first central wheel about the central axis causes rotary motion of the threaded part of the gear device and translatory motion of the threaded part of the second output device.

34. Pipetting device according to claim 29, wherein the first central wheel is connected to a first coupling device of the pipetting device and the orbital wheel is connected to a second coupling device of the pipetting device, the pipetting device has a blocking device which can be selectively coupled to the first coupling device or to the second coupling device, when the blocking device is coupled to the first coupling device, rotation of the first central wheel about the central axis is blocked and thus the second output device is blocked, and when the blocking device is coupled to the second coupling device, a rotation of the orbital wheel about the central axis is blocked and thus the first output device is blocked.

35. Pipetting device according to claim 19, wherein the first output device is coupled to a displacement device that comprises a piston and a cylinder, the piston being movably arranged in the cylinder, an ejector device is provided for ejecting a pipette tip attached to the displacement device, which can be ejected from the displacement device and/or the pipetting device, and the gear device transmits a rotary motion of the electric motor to the ejector device for ejection of the pipette tip from the pipetting device, and the ejector device is motionally coupled to the second output device.

36. Pipetting device according to claim 19, wherein the pipetting device has a coupling apparatus for releasably coupling a piston-cylinder arrangement to the pipetting device, the gear device is operable to transmit rotary motion of the electric motor to the coupling apparatus for releasing the piston-cylinder arrangement from the pipetting device, and the coupling apparatus is motionally coupled to the second output device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG. 1 schematically shows in a perspective view a first preferred embodiment of a pipetting device according to the invention,

[0071] FIG. 2 schematically shows in a perspective view a part of a second preferred embodiment of a pipetting device according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0072] FIG. 3 schematically shows a section through a part of the pipetting device of FIG. 2, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0073] FIG. 4 schematically shows in a perspective view a part of a third preferred embodiment of a pipetting device according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0074] FIG. 5 schematically shows in a perspective view a part of a fourth preferred embodiment of a pipetting device according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0075] FIG. 6 schematically shows in a perspective view a part of the pipetting device from FIG. 5, namely a part of a planetary gearing according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0076] FIG. 7 schematically shows in a perspective view a part of the pipetting device from FIG. 5, namely a part of a gear device according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0077] FIG. 8 schematically shows in a perspective view a part of the pipetting device from FIG. 5, namely a part of a gear device according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0078] FIG. 9 schematically shows a section through a part of the pipetting device from FIG. 5, namely through a part of a gear device according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0079] FIG. 10 schematically shows in a perspective view a part of the pipetting device from FIG. 5 in a first state, wherein a simplified representation has been chosen with omission of parts of the pipetting device,

[0080] FIG. 11 schematically shows in a perspective view the part of the pipetting device from FIG. 10 in a second state, wherein a simplified representation has been chosen with omission of parts of the pipetting device, and

[0081] FIG. 12 schematically shows in a perspective view a fifth preferred embodiment of a pipetting device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0082] FIG. 1 shows schematically in a perspective view a preferred embodiment of a pipetting device 1 according to the invention for receiving and dispensing fluid volumes. This pipetting device 1 is a pipetting device 1 based on the air cushion principle. The pipetting device 1 has a displacement device 2, in particular a piston-cylinder arrangement, with a displacement element 3, in particular a piston, and a displacement housing 4, in particular a cylinder. The displacement element 3 is movably arranged within the displacement housing 4.

[0083] A pipette tip 7 (not shown in FIG. 1) is attachable to the displacement device 2. The pipette tip 7 is separable and/or ejectable from the displacement device 2. A pipette tip 7 can be connected to the displacement device 2 by means of a plug connection. For this purpose, the pipetting device 1 has a conically designed end piece 5 on the displacement device 2, onto which a pipette tip 7 with a corresponding opening can be plugged.

[0084] For separating and/or ejecting a pipette tip 7 from the displacement device 2, an ejector device 6 is provided on the pipetting device 1.

[0085] FIG. 2 shows schematically in a perspective view a part of a second preferred embodiment of a pipetting device 1 according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1. This pipetting device 1 is also a pipetting device 1 based on the air cushion principle. Compared to the pipetting device 1 of FIG. 1, the pipetting device 1 of FIG. 2 has a differently dimensioned displacement device 2. A pipette tip 7 is attached to the displacement device 2, in particular to its end piece 5.

[0086] In FIG. 2, it can be seen that in the illustrated and preferred embodiment example, the pipetting device 1 has a drive device 8 with an electric motor 9, in particular with exactly one electric motor 9. Furthermore, the pipetting device 1 has a gear device 10 with a first output device 11. The gear device 10 is driven by the electric motor 9 by means of a rotary motion and is designed to transmit a rotary motion of the electric motor 9 to the first output device 11. Here, the gear device 10 is designed to convert or transform a rotary motion of the electric motor 9 into a translatory motion of the first output device 11. In the preferred embodiment example shown in FIG. 2, the first output device 11 is motionally couplable to the electric motor 9, so that in the coupled state a rotary motion of the electric motor 9 is converted/transformed into a translatory motion of the first output device 11.

[0087] In the illustrated and preferred embodiment example, the gear device 10 has a second output device 12 and is designed to transmit a rotary motion of the electric motor 9 to the second output device 12. Here, the gear device 10 is designed to convert or transform a rotary motion of the electric motor 9 into a translatory motion of the second output device 12. In the preferred embodiment example shown in FIG. 2, the second output device 12 is motionally couplable to the electric motor 9, so that in the coupled state a rotary motion of the electric motor 9 is converted/transformed into a translatory motion of the second output device 12.

[0088] In the illustrated and preferred embodiment example, exactly one electric motor 9 (the electric motor 9 of the drive device 8) is provided for driving the first output device 11 and the second output device 12.

[0089] FIG. 3 schematically shows a section through a part of the pipetting device 1 of FIG. 2, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1. In the illustrated and preferred embodiment example, the gear device 10 has a threaded nut 15 which is motionally couplable with the electric motor 9, so that in the coupled state a rotary motion of the electric motor 9 causes a rotary motion of the threaded nut 15. The first output device 11 has a threaded spindle 13 engaged with the threaded nut 15. The threaded spindle 13 is secured against rotation. Through the gear device 10, a rotary motion of the electric motor 9 causes a rotary motion of the threaded nut 15 and a translatory motion of the threaded spindle 13.

[0090] The threaded spindle 13 is motionally coupled to the displacement element 3, here by means of a magnet 16 of the pipetting device 1.

[0091] In the illustrated and preferred embodiment example, the gear device 10 has a rotationally movable threaded part 17 that is motionally couplable to the electric motor 9 so that in the coupled state a rotary motion of the electric motor 9 causes a rotary motion of the threaded part 17 of the gear device 10. The second output device 12 has a translationally movable threaded part 14 having a hollow cylindrical portion. The threaded part 14 of the second output device 12 engages with a rotationally movable threaded part 17 of the gear device 10, here with an external thread of the threaded part 17 of the gear device 10. Through the gear device 10, a rotary motion of the electric motor 9 causes a rotary motion of the threaded part 17 of the gear device 10 and a translatory motion of the threaded part 14 of the second output device 12.

[0092] The second output device 12, in particular the threaded part 14 of the second output device 12, is motionally coupled to the ejector device 6.

[0093] In the illustrated and preferred embodiment example, the ejector device 6 of the pipetting device 1 is designed in such a way that a pipette tip 7 attached to the displacement device 2 is movable relative to the displacement device 2 and finally ejectable from the displacement device 2 and the pipetting device 1.

[0094] The gear device 10 is designed to transmit a rotary motion of the electric motor 9 to the ejector device 6 and to convert/transform it into a translatory motion of the ejector device 6, which results in the ejection of a pipette tip 7 attached to the displacement device 2 from the displacement device 2.

[0095] FIG. 4 shows schematically in a perspective view a part of a third preferred embodiment of a pipetting device 1 according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1. In comparison to the pipetting device 1 according to FIGS. 2 and 3, the pipetting device 1 according to FIG. 4 additionally has a switching device 27. This switching device 27 is explained in more detail with reference to FIGS. 10 and 11.

[0096] In all illustrated and preferred embodiment examples, the second output device 12, namely the threaded part 14 of the second output device 12, is arranged coaxially to the first output device 11, namely to the threaded spindle 13 of the first output device 11. The axis of motion of the threaded part 14 of the second output device 12 coincides with the axis of motion of the threaded spindle 13. This axis of motion corresponds to the central longitudinal axis of the pipetting device 1. The threaded part 14 of the second output device 12 has a hollow cylindrical portion which surrounds at least part of the threaded spindle 13. At least a part of the threaded spindle 13 is arranged in a hollow space delimited by the hollow cylindrical portion of the threaded part 14 of the second output device 12.

[0097] FIG. 5 shows schematically in a perspective view a part of a third preferred embodiment of a pipetting device 1 according to the invention, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1. In comparison with the embodiment examples according to FIGS. 2 to 4, the gear device 10 of the pipetting device 1 according to FIG. 5 has an epicyclic gearing 18 with [0098] a first central wheel 19, which has a hollow space 20, [0099] a second central wheel 21, which is arranged centrally in the hollow space 20 of the first central wheel 19, is driven by the electric motor 9 and thereby rotates about a central axis 22, and [0100] three orbital wheels 23, each orbital wheel 23 being rotatable about an orbital axis 24 and being arranged between the first central wheel 19 and the second central wheel 21 in the hollow space 20 and being engaged with the first central wheel 19 and the second central wheel 21, respectively.

[0101] The first central wheel 19 and/or a carrier 25 of the respective orbital wheel 23 rotates/rotate about the central axis 22.

[0102] Such an epicyclic gearing 18 is also referred to as a planetary gearing 18, wherein the first central wheel 19 is also referred to as a hollow wheel 19, the second central wheel 21 is also referred to as a sun wheel 21, the orbital wheels 23 are also referred to as planetary wheels 23, and the carriers 25 of the planetary wheels are also referred to as planetary wheel carriers 25.

[0103] An advantage of this design is the compact and predominantly axially aligned construction.

[0104] A part of the epicyclic gearing 18 of the pipetting device 1 from FIG. 5 is shown schematically in FIG. 6 in a perspective view, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1.

[0105] In the illustrated and preferred embodiment example, the first central wheel 19 has toothing on an inner side. This toothing of the first central wheel 19 can have, for example, between 30 and 90 teeth—here, this toothing of the first central wheel 19 has, by way of example, 60 teeth. Each orbital wheel 23 has a toothing on an outer side. The toothing of each orbital wheel 23 may have, for example, between 12 and 48 teeth—here this toothing of each orbital wheel 23 has, by way of example, 24 teeth. The second central wheel 21 has a toothing on an outer side. This toothing of the second central wheel 21 may have, for example, between 6 and 24 teeth—here, this toothing of the second central wheel 21 has, by way of example, 12 teeth. The toothing of each orbital wheel 23 engages/meshes with both the toothing of the first central wheel 19 and the toothing of the second central wheel 21. The gear module is preferably between 0.2 mm and 0.8 mm, in particular 0.4 mm.

[0106] The part of the epicyclic gearing 18 from FIG. 6 and further parts of the gear device 10 of the pipetting device 1 from FIG. 5 are shown schematically in a perspective view in FIGS. 7 and 8, respectively, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1.

[0107] Details of the pipetting device 1 from FIG. 5, in particular the of gear device 10, are shown in the sectional view of FIG. 9.

[0108] In the preferred embodiment example shown here, each orbital wheel carrier is motionally coupled to an orbital wheel 23 and to the threaded nut 15. Each orbital wheel 23 is motionally coupled to the first output device 11, in particular to the threaded spindle 13, by means of the respective orbital wheel carrier 25. A rotary motion of the orbital wheels 23 about the central axis 22 causes a rotary motion of the orbital wheel carriers 25 about the central axis 22, which causes a rotary motion of the threaded nut 15 of the gear device 10, which—due to the anti-rotation lock of the threaded spindle 13—causes a translational motion of the threaded spindle 13.

[0109] In the illustrated and preferred embodiment example, the first central wheel 19 is motionally coupled to the second output device 12. In particular, a connecting element 26 is attached to the first central wheel 19, here there are three connecting elements 26. Each connecting element 26 is connected and/or motionally coupled to the threaded part 17 of the gear device 10. A rotary motion of the first central wheel 19 about the central axis 22 causes a rotary motion of the threaded part 17 of the gear device 10 and a translational motion of the threaded part 14 of the second output device 12.

[0110] In the illustrated and preferred embodiment example, the gear device 10 is designed to transmit a rotary motion of the electric motor 9 in a geared manner to the second output device 12, here with a gear ratio of −5. In addition, the gear device 10 is designed to transmit a rotary motion of the electric motor 9 in a geared manner to the first output device 11, here with a gear ratio of 6. Both with regard to the first output device 11 and with regard to the second output device 12, it is possible to select other gear ratios or no gearing-up/gearing-down.

[0111] In the illustrated and preferred embodiment example, the electric motor 9 has a holding torque of between 3 mNm and 12 mNm, in particular of 8 mNm.

[0112] In the illustrated and preferred embodiment example, the ejector device 6 can exert a force of between 20 N and 180 N, further preferably of 80 N to 120 N, in particular of 100 N on a pipette tip 7 attached to the displacement device 2.

[0113] FIG. 10 shows schematically in a perspective view a part of the pipetting device 1 from FIG. 5 in a first state, wherein a simplified representation has been chosen with omission of parts of the pipetting device 1.

[0114] In the illustrated and preferred embodiment example, the pipetting device 1 has a switching device 27. By means of the switching device 27, the gear device 10 is switchable in such a way that the gear device 10 moves either the first output device 11 or the second output device 12 when the gear device 10 is driven by the electric motor 9. By means of the switching device 27, selectively the first output device 11 or the second output device 12 is blockable.

[0115] It is preferred that—as shown—the switching device 27 has a blocking device 28 for blocking at least one component of the gear device 10. The blocking device 28 is designed in particular for blocking the first output device 11 and/or the second output device 12.

[0116] In the illustrated and preferred embodiment example, the blocking device 28 is driven by an activator 29 of the switching device 27, which activator 29 here has a further electric motor 30. The blocking device 28 is arranged on a shaft 31 of the electric motor 30. By means of the electric motor 30 and a threaded arrangement, the blocking device 28 is axially adjustable relative to an axis of rotation of the gear device 10 and axially adjustable relative to an axis extending through the shaft 31 of the electric motor 30.

[0117] In the illustrated and preferred embodiment example, the pipetting device 1 has a first coupling device 32 with projections 33 and a second coupling device 34 with projections 35. The first central wheel 19 is connected to the first coupling device 32 in a rotationally fixed manner and the orbital wheels 23 are connected to the second coupling device 34 in a rotationally fixed manner. The blocking device 28 is selectively couplable to the first coupling device 32 or the second coupling device 34.

[0118] In the first state shown in FIG. 10, the blocking device 28 is coupled to the second coupling device 34, namely a projection 36 of the blocking device 28 is arranged between two projections 35 of the second coupling device 34. In this first state, the blocking device 28 is not coupled to the first coupling device 32.

[0119] In the second state shown in FIG. 11, the blocking device 28 is axially displaced in the direction of the first coupling device 32 and coupled to the first coupling device 32, namely a (different) projection 36 of the blocking device 28 is arranged between two projections 33 of the first coupling device 32. In this second state, the blocking device 28 is not coupled to the second coupling device 34.

[0120] In particular, thus, a projection 36 of the blocking device 28 can be engaged with one projection 33 or with a plurality of projections 33 of the first coupling device 32 and/or a projection 36 of the blocking device 28 can be engaged with one projection 35 or with a plurality of projections 35 of the second coupling device 34, but this not simultaneously but exclusively successively or alternately.

[0121] When the blocking device 28 is coupled to the first coupling device 32, rotation of the first central wheel 19 about the central axis 22 is blocked. Thus, the second output device 12, i.e., a movement/motion of the second output device 12, is also blocked. Rotation of the first central wheel 19 about the central axis 22 is not possible, and rotation of the second central wheel 21 about the central axis 22—caused by the electric motor 9—causes rotation of the orbital wheel carriers 25 about the central axis 22, which causes rotation of the threaded nut 15. This results in a translatory movement/motion of the threaded spindle 13.

[0122] When the blocking device 28 is coupled to the second coupling device 34, rotation of the orbital wheels 23 about the central axis 22 is blocked. Thus, the first output device 11, i.e. a movement/motion of the first output device 11, is blocked. Rotation of the orbital wheels 23 and the orbital wheel carriers 25 about the central axis 22 is not possible. Rotation of the second central wheel 21 about the central axis 22—caused by the electric motor 9—causes rotation of the first central wheel 19 about the central axis 22, which causes rotation of the threaded part 17 of the gear device 10. This results in a translatory movement/motion of the second output device 12.

[0123] It is not shown that the pipetting device 1 has an operating element for controlling the electric motor 9. It is provided here that the blocking device 28 and/or the activator 29 are/is also controllable by means of this operating element. This permits simple and convenient handling.

[0124] FIG. 12 shows schematically in a perspective view a further embodiment of a pipetting device 1 according to the invention. Here, it is a dispenser for receiving and dispensing fluid volumes, based on the positive displacement principle.

[0125] The dispenser has a drive device 8 as previously described and a gear device as previously described and a switching device 27 as previously described.

[0126] The dispenser also has a coupling apparatus (not shown) for releasably coupling a displacement device 2 to the dispenser. In this case, the displacement device 2 is designed as an exchangeable piston-cylinder arrangement. The gear device 10 of the dispenser is designed to transmit a rotary motion of the electric motor 9 to the coupling apparatus, which results in the release of a displacement device 2 coupled to the dispenser from the dispenser. For this purpose, the coupling apparatus is motionally coupled to and/or movably driven by the second output device 12 of the gear device 10 of the dispenser. Preferably, the gear device 10 is designed to transmit a rotary motion of the electric motor 9 to the second output device 12 in a stepped-down or stepped-up manner.

TABLE-US-00001 List of references: 1 Pipetting device 2 Displacement device 3 Displacement element of 2 4 Displacement housing of 2 5 End piece of 2 6 Ejector device of 1 7 Pipette tip of 2 8 Drive device of 1 9 Electric motor of 8 10 Gear device of 1 11 First output device of 10 12 Second output device of 10 13 Threaded spindle of 11 14 Threaded part of 12 15 Threaded nut of 10 16 Magnet of 1 17 Threaded part of 10 18 Epicyclic gearing of 10 19 First central wheel of 18 20 Hollow space of 19 21 Second central wheel of 18 22 Central axis of 18 23 Orbital wheels of 18 24 Orbital axis of 23 25 Orbital wheel carrier for 23 26 Connecting element of 10 27 Switching device of 1 28 Blocking device of 27 29 Activator of 27 30 Electric motor of 29 31 Shaft of 30 32 First coupling device of 1 33 Projections of 32 34 Second coupling device of 1 35 Projections of 34 36 Projections of 28